SYNOPSIS OF GFNER I 



XXXI 



1883. Dabnanites, Novak. Zur Kennt. bohm. Trilob. 

 1SS4. Dtii mil ii lbs, Novak. Studien an Hypostomen, ii. 



1884. Dahnanites, Walcott. Palseontol. Eureka Dist. 

 18S5. Dahnanites., Clarke. Geol. Su sion in Ontario Co. 



18S5. Dahnanites, CEhlbht. Bull, de la Soc. d'Etudea Scientif. d. Angers. 



L886. Dahnanites, Barrois. Bull, de la Soc. giol. de France. 



1887. Dahnanites, Fosrstb. Bull Denison. Univ. 



The species of the genus Dalmanites frequently exhibit a tendency to varia- 

 tion in many of their more important features. This variability may be either 

 in the relative development of the lateral glabellar furrows, the coalescence of 

 the glabellar lobes, or in the ornamentation of the margins of the cephalon and 

 pygidium ; the features of the glabella are of more distinctive importance, 

 the ornamental characters undoubtedly being of a somewhat more fugitive 

 value. By the unequal development and suppression of the glabellar lobes 

 and furrows, there is an evident transition from the typical Dalmanites to the 

 typical Phacops. Again, the gradual coalescence of the lateral glabellar lobes 

 produces forms following the type of the genus Chnsmops, in which the first two 

 pairs are united, and of the genus Monorakos, in which the three lobes of each 

 side are coalesced. The ornamental features are of importance in the establish- 

 ment of subordinate groups of a provisional character. It is here proposed to 

 group under the term Hansmannia the typical and unvaried forms of Dalmanites 

 which follow the type of D. caudatus, (Briinnich) Emmrich, and I). Hausmanni, 



Brongniart. 



Sub-genus H A U S M A N N I A ; 



Diagnosis. Body elongate-ovate, depressed- 

 convex. Cephalon lunate ; genal angles produced 

 into spines; glabella scarcely prominent; frontal 

 lobe transverse or sub-rhomboidal ; all the lateral 

 lobes well developed. Thorax composed of eleven 

 segments; pleurae beveled, the posterior segments 

 often produced. Pygidium large, bearing more 

 than eleven ampliations; margin entire, often pro- 

 duced into a caudal spine. 



The Devonian species, which are referred to 

 this group, are to some extent imperfectly known, and it may eventually 



N. S.-G. 



